The invention relates to a device for accommodating expansion absorption in fluid circulation systems, in particular of heating or cooling installations, having at least one expansion vessel preferably in gas exchange with the atmosphere, into which liquid from the fluid circulation system is received and from which liquid is returned to the fluid circulation system via a pressure pump. An overflow valve which is adjustable to the operating pressure of the installation is provided in one conduit of the expansion vessel, so that a lower pressure prevails in the expansion vessel than in the fluid circulation system.
It is known that in heating installations, due to the heating or cooling of the heating fluid (water), a volume change occurs. Upon heating, the additional volume must be taken out of the fluid circulation, and upon cooling, returned into the fluid circulation again. In such heating installations it is known practice to transfer the excess heating fluid resulting from the thermal expansion into an open expansion vessel and upon cooling to supply heating fluid to the fluid circulation again via a pump.
Further also closed expansion vessels are known for this purpose. In this connection it is current practice to open a solenoid valve when a certain positive pressure is reached in the fluid circulation and to transfer the heating fluid from the circulation into the expansion vessel. When the pressure drops in the installation, the forcing pump is turned on and heating fluid is pumped from the expansion vessel into the fluid circulation. An example of such an installation can be seen in German patent document DE-A1-2,516,424. By this intermittent removal from and return of heating fluid into the fluid circulation considerable pressure fluctuations occur in the installation. Similar conditions appear also in cooling installations.